Distribution of data to multiple recipients

ABSTRACT

In a trading system market data from a matching engine is distributed by a broker to a plurality of trading floors repeatedly every T seconds, typically one second. This one second distribution period is divided into a plurality of time slots and each trading floor is randomly assigned to a slot. Data for a given trading floor is calculated and distributed during the time slot assigned to that floor. The position of a trading floor relative to others is varied by swapping a pair of adjacent time slots every J distribution periods.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.11/530,294, filed Sep. 8, 2006, which claims benefit under 35 U.S.C.119(e) of U.S. Provisional Application No. 60/715,355, filed Sep. 8,2005, the entirety of each of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to the distribution of data from a data source tomultiple recipients. It is particularly concerned with the distributionof time critical data for example from trading systems to trader devicestrading on the system in which relative delay of trading data from onedevice to another can affect the ability to trade effectively

BACKGROUND TO THE INVENTION

There are many examples in the art of computerised, automated tradingsystems which enable parties to buy and sell products by entry oftrading information. Trading systems are widely used in the financialindustry, for example, to trade financial products such as equities,commodities, FX products and other financial instruments. One example ofa known trading system used to trade FX spot is disclosed in U.S. Pat.No. 5,375,055 of Togher et al. The system described in this publicationis an anonymous trading system in which counterparties submit ordersinto the market without revealing their identity. A party trading on thesystem does not know the identity of a counterparty to a deal until thedeal has been completed. To avoid parties entering into trades withparties they consider to be untrustworthy, the system uses bilateralcredit limits. Each party submits details of the credit they extend toeach other possible counterparty on the system. If a party does not wishto trade with a certain counterparty they extend no credit to thatcounterparty. The system filters visible quotes (bids and offers)entered into the system and only displays to a given counterparty,visible quotes originating from parties with whom they have bilateralcredit. The determination of whether a quote should be seen is made onthe basis of a yes/no credit matrix, but before a deal is completed thecredit of each counterparty to the deal is check to ensure that bothhave sufficient credit for the amount of the deal. If they do not, theamount of the deal may be reduced to conform to the credit available.

The system disclosed in U.S. Pat. No. 5,375,055 has been embodied formany years in the EBS Spot trading system operated by EBS Group Limitedof London UK. The system comprises a group of matching engines orarbitrators which receive quote information from trader devices on thesystems and match quotes to complete deals, subject to credit checking.The arbitrators also distribute market data to trader devices via anintermediate node which prepares a market view to enable traders to seethe quotes that are being made by other traders in the market as well asproviding them with other information regarding the state of the market.The EBS system only shows the trader devices the best price that theycan deal a regular amount, defined as a basic volume in the instrumentbeing traded, for example $10 Million; the best dealable priceavailable, which might be for a smaller volume, and the best price onthe system, which will be different if the trading floor to which thetrader device is attached does not have bilateral credit with theprovider of the quote.

In the Togher system, market distributors prepare individual marketviews for each trading floor based on their credit, so that each tradingfloor will see a different, personalised view of the market. The marketviews are distributed via bank nodes which hold actual credit limits andwhich perform the final credit checks before a deal is completed. Thetrader devices may be conventional workstations through which tradersinput quoted, usually via a dedicated keypad and which include a displayof market information enabling the trader to monitor the market and somake trading decisions. Alternatively, there may be automated tradinginterfaces which are computers which submit orders into the market underthe control of a trading model or algorithm which responds to marketdata received from the system. In a more recent version of the system,the market distribution and bank node functions are integrated withinbroker nodes.

In any trading system there exists an issue of fairness in thedistribution of quotes which can be traded. If one trader sees a quotebefore another trader they are able to deal that quote before it hasbeen seen by that trader. If this advantage is built into the system thesystem lacks credibility and many parties will not see the benefit oftrading on it. Issues of quote distribution are not material in slowmoving markets, or in systems where quotes are guaranteed to beavailable to a certain period of time, such as is the case in manyInternet based systems in which latency is hard to control. However, invery fast moving markets such as the interbank FX spot market they arecritical.

The relative time at which quotes are received by trader devices dependspartly on the location of the trading device with respect to thedistribution device, in this case the arbitrator, and partly on themanner in which the quotes are distributed. As messages from the systemtake a finite time to travel to the trader terminals, those terminalsthat are physically closer to the arbitrator have an advantage. Inpractice, many of the trading floors using the EBS system areconcentrated around the physical location of the arbitrators which arein the major FX trading centres: London New York and Tokyo. In theTogher system, prices are distributed to trader devices every secondwith the order of distribution being determined by when the tradingfloor logged on to the system. Thus one trading floor may log on at 80mS past the second and another trading floor at 120 mS past the second.The floors will always have quotes distributed to them at 80 and 120 mSpast the second respectively. If a new quote is available on thearbitrator for distribution at 60 mS past the second, the 80 mS tradingfloor will see it first and be able to trade it first. If a new quote isavailable at 100 mS, the 120 mS trading device will see it first as the80 mS device will not see it for 980 mS, 960 mS after the 120 mS device.Situations can arise where, for a while, one trading floor is repeatedlyseeing quotes slightly after another trading floor. This situation canlast for a long time and is not limited to floors receiving data fromthe same source. It could be caused by proximity to floors on othermarket distributors. A trading floor's relative position is determinedby when the floor's banknode first connects to an arbitrator after anarbitrator restart.

More recently the architecture of the EBS system has been altered andthe market distributors and market access nodes, or bank nodes, of theTogher system have been replaced by broking nodes. Broking nodes, orbrokers, sit logically between the trading devices and the arbitratorsand are responsible for a number of system functions, includingdistribution of quotes to the trader devices, as well as the submissionof hits and quotes to the arbitrators, credit check and the storage oftrade settlement instructions. Unlike the distribution system of thearchitecture disclosed in U.S. Pat. No. 5,375,055, the brokersdistribute quotes received from the arbitrator to which they areconnected once per second. The broker receives the quotes from thearbitrators, calculates the market view for each of the trading floorsconnected to it and distributes the market view for each trading floor,in turn, as quickly as it can. There are two key differences in thisapproach, both of which lead to fairness problems. First, the marketviews are prepared from the same quote information received from thearbitrator. In the previous version, market views were prepared from thequote information at the particular slot assigned to the trading floorthat was slightly different for each floor. Second, as the market viewsare distributed in turn, a particular trading floor will always receiveits data at a fixed time apart from any other trading floor. This canlead to a situation where, for example, a large trading floor having thehighest speed communications available, and very quickly respondingautomated trading interfaces receives its data a little before a smallertrading floor which lower specification communications and a tradingfloor having only manual traders who are slower to react thancomputerised trading interfaces. The result is that the smaller floorwill miss the quotes they want to hit every time the larger floor wantsto trade them as the larger floor will have hit the quotes by the timethe smaller floor sees them. This is disadvantageous to the smallerfloor and leads to perceptions of unfairness in the system which cancast doubt over the integrity of the system. The problem may becharacterised as one of long term firing proximity. It is the sameproblem as arises with the Togher architecture, as described above butis actually worse as a trading floor's position with respect to otherfloors on the broker is fixed and does not change when the floor logs onagain, for example on the next trading day.

A further problem is that some floors will receive data a relativelylong time after it was provided by the arbitrator and the market viewwas calculated. Regardless of the problems of others connected to thebroker receiving the data first, the data is now ageing. This problemmay be referred to as one of computation to delivery latency.

SUMMARY OF THE INVENTION

The invention aims to address the problems of unfairness discussedabove. Broadly, one aspect of the invention resides in the provision ofa system and method in which a data distribution period is divided intoa number of slots and users, or data recipients, are each assigned to atime slot. The data to be distributed to a given receipent is calculatedand distributed during that user's time slot. In another aspect of theinvention a random slot in the data distribution period is calculatedand the position of that random slot in the period is swapped, togetherwith any data receiver assigned to that time slot, with another timeslot.

More specifically, there is provided a method of periodicallydistributing data to a plurality of data receivers, comprising: dividinga data distribution period into a plurality of time slots; assigningeach of the data receivers to a respective one of the time slots; andfor each time slot having an assigned data receiver, during the timeslot, calculating the data to be sent to the data receiver and sendingthe data to the data receiver.

This aspect of the invention also provides apparatus for periodicallydistributing data to a plurality of data receivers, comprising: a datadistributor for distributing data to data receivers over a datadistribution period, the data period being divided into a plurality oftime slots; the data distributor comprising a slot assignor forassigning each of the data receivers to a respective one of the timeslots; and a data calculator for calculating, during the time slot, foreach time slot having an assigned data receiver, the data to be sent tothe data receiver, the data distributor sending the data to the datareceiver within the time slot.

Embodiments of this aspect of the invention have the advantage thatcomputation to delivery latency is reduced as each data recipient hasits data calculated separately during the time slot in which the data issent to it.

Preferably, the data recipients are assigned to time slots randomlywhich has the advantage that data distribution tends to be uniformlyspaced throughout the data distribution period. This maximises the timeavailable for data distribution within the distribution period.

Preferably, in a system which has a number of data distributors, forexample a number of brokers in a trading system, each data distributoris configured to have the same data distribution period and the samenumber of time slots per period. This arrangement has the advantage thatthere is no advantage to the data recipient in receiving their data fromany particular data distributor so eliminating perceptions of unfairnessfrom the data distribution.

Preferably, data receivers are only sent data only M data distributionperiods. This has the advantage of making the frequency with which eachrecipient's data is updated configurable on an individual basis.Preferably, the data distribution period is divided into a number ofblocks, each having a number of slots and the data distribution periodis processed block by block. Preferably, a delay parameter may bedefined to delay the distribution of data to a given receiver by apredetermined amount.

The invention also resides in a method of periodically distributing datato a plurality of data receivers, comprising: dividing a datadistribution period into a plurality of time slots; assigning each ofthe data receivers to a respective one of the time slots; and for eachtime slot having an assigned data receiver, every M data distributionperiods, where M is defined for each data receiver, during the timeslot, calculating the data to be sent to the data receiver and sendingthe data to the data receiver.

According to a second aspect of the invention, there is provided amethod of periodically distributing data to a plurality of datareceivers, comprising: dividing a data distribution period into aplurality of time slots; assigning each of the data receivers to arespective one of the time slots for distribution of data; on every Jthdata distribution period: selecting a random slot of the plurality ofslots in the data distribution period; and swapping the position of thatrandom slot in the data distribution period, together with any datareceiver assigned to that time slot, with another time slot.

This aspect of the invention also provides apparatus for periodicallydistributing data to a plurality of data receivers, comprising: a datadistributor for distributing data received from a data source to datareceiver over a data distribution period, the data distribution periodbeing divided into a plurality of time slots; the data distributorcomprising a slot assignor for assigning each of the data receivers to arespective one of the time slots for distribution of data; and a slotposition swapper, for every Jth data distribution period selecting arandom slot of the plurality of slots in the data distribution periodand swapping the position of that random slot in the data distributionperiod, together with any data receiver assigned to that time slot, withanother time slot.

Embodiments of this aspect of the invention have the advantage that longterm price firing proximity, wherein one data recipient always receivesdata shortly after another, is avoided. Preferably, the time slots thatare swapped are adjacent. This, in combination with performing the swaponly after ever Jth distribution period, enables the firing order fordata distribution to be slowly re-arranged in small intervals without itbeing noticeable to the data recipients.

Preferably, the adjacent time slot is the one after the randomlyselected time slot and the swap is performed before the data iscalculated. Thus, data is calculated and sent first for data recipientthat was in the time slot after the randomly selected time slot beforethe swap is made. This avoids the problem of hopping which can occur ifthe swap is made just after data has been sent to a data recipientcausing it to be sent twice in a very short time to one recipient and tomiss nearly a whole distribution period for another recipient.

The invention also resides in a method of periodically distributing datato a plurality of data receivers, comprising: dividing a datadistribution period into a plurality of time slots; assigning each ofthe data receivers to a respective one of the time slots fordistribution of data; and performing a low frequency shuffle of theorder of the time slots relative to the data distribution frequency.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention, will now be described, by way of exampleonly, and with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a known trading system to whichembodiments of the invention may be applied;

FIG. 2 is a view of a distribution timeslice having a number of firingslots;

FIG. 3 illustrates the operation of a first embodiment of the invention;and

FIG. 4 illustrates the operation of a second embodiment of theinvention.

The trading system of FIG. 1 is largely as described in the introductionabove and is a known trading system. In addition to the arbitrator 10(other arbitrators are not shown for simplicity), broker 12 (only one ofwhich is shown), and trading devices 24, shown here as traderworkstations, the system includes city node 30 which is responsible fordistribution of market data and news, as opposed to quote and dealrelated information, a log manager 32 which maintains a record ofarbitrator activity and is used for customer billing 34 and forresolving trading discrepancies via help desk 36. A gateway 14interfaces the broker with the arbitrator and the city node and a datastore 38 holds a record of broker activity. Details of completed dealsare provided by the broker to a deal feed server 40 which generates dealtickets which are sent to the counterparties to a deal where they arereceived by a deal feed client computer 20 on the trading floor. Thetrading tickets are used to record the banks position by positionkeeping systems 28 and to settle trades with counterparties. The tradingfloor shown is one of a number on the system. Floors A, B and C areshown as connected to the broker 12. As well as the trader devices(workstations and/or automated trading interface), each floor willinclude a trading floor administrator 42 which interfaces with thesystem to enable an administrator to communicate floor details such astrader identifications and privileges and floor credit limits to thesystem. The broker 12 is one of a plurality of brokers. Each broker onthe system may have a number of trading floors connected to it,typically in the order of 10 to 50. It is important that the manner inwhich quotes are distributed is not affected by the number of floorsattached to the broker.

The system of FIG. 1 is purely exemplary. The present invention is notlimited to distribution of quotes in a broker or other distributed typeof trading system, it is applicable to any system where is desired todistribute data fairly to a number of parties. This may be a tradingsystem having a different type of architecture such as a centralisedsystem or it may be a system other than a trading system in which thefairness and timeliness of data is important. The invention is notlimited to any particular trading system architecture or even to tradingsystems but has applicability to any system for distributing data,particularly live data, to a number of parties.

In the anonymous trading system of FIG. 1, the brokers distribute quotesreceived from the arbitrators at a predetermined frequency, for exampleonce per second. The arbitrators are a data source providing data to thebrokers, each of which are an example of a data distributor. The brokersdistribute the data to trading floors which are examples of datarecipients. Although the example described is a trading system, theprinciples apply to any system for distribution of live, or timecritical, data. This period, which is a fixed distribution period ortimeslice, is not fixed and any other suitable period could be chosen.FIG. 2 shows how this timeslice 50 may be sliced or divided into anumber of time slots 52. In this example the number of time slots is 40but this number is variable and a matter of system design choice. Thenumber of time slots may be represented by N. The timeslice has aduration T and each slot within the timeslice has a duration t. It ispreferred that t is the same for each time slot but this is notessential. To ensure fairness across the entire system, it is preferredthat all brokers are configured with the same length T of timeslice andthe same number of time slots N each having the same length t. Tradingfloors are assigned to time slots randomly as each floor subscribes tomarket views. This is a one-off assignment when the floor firstsubscribes and is connected to the broker.

As well as assigning actual trading floors to time slots, a market datapseudo-floor may be assigned to a vacant time slot. This pseudo-floor isused for calculation and distribution of market data which is sent toall recipients regardless of the bilateral credit. One example is thebest prices that is available on the system.

The timeslice is fixed by reference to the system clock of the brokerenabling it to be kept accurately. In some cases, where the market isvery active, there may be difficulties in calculating and sending a fullmarket view in a time slot, leading to some slot drift, but this can bemade up over subsequent firing events.

Thus each time slot corresponds to a precise firing time when the marketview is calculated for the trading floor assigned to the time slot. Thiscontrasts with the prior art approach in which market views for allfloors were first calculated and then distributed. After calculation,the market view is sent to the subscribing floor with calculation anddistribution both being performed within the time slot. Data from thearbitrator is received by the broker continuously. Thus the market viewfor each trading floor is calculated at a slightly different time fromslightly different data. The use of time slots with calculation ofmarket view data within the time slot for a given recipient overcomesthe problem of computation to delivery latency discussed above.Moreover, by assigning floors to time slots randomly, an efficientdistribution of quote firing is achieved.

FIG. 3 illustrates a solution to the problem of long term firingproximity. In essence, a low frequency shuffle is used to change theposition of a pair of firing time slots. Preferably, these time slotsare adjacent. Preferably, during the last of a configurable number oftimeslices the contents of a randomly selected adjacent pair of firingtime slots is exchanged. It is important that each trading floorreceives market views as close to the timeslice interval T as possibleas any large variation could temporarily distort the market view. Inorder to achieve this the pitch of the time slots must be small.Preferably the pitch is in the order of 1/20^(th) the timeslice. WhereT=1000 mS, the pitch P=50 mS. This requires that the number of timeslots is great enough for the timeslice to be divided up so that eachtime slot is not larger than 1/20^(th) of the timeslice. The figure of1/20^(th) is preferred for an FX trading market, greater or lesser sizesmay be appropriate in other markets or applications of the embodiment ofthe invention.

It will be appreciated that in many instances, the number of time slotswill be greater than the number of trading floors connected to thebroker. It is preferred that the time slots selected for swapping areswapped regardless of whether there is a trading floor assigned to oneor both of the time slots, but there will be no effect on the relativepositions unless there is a floor in one of the pair of time slots. Inthis case there will simply be one pass of the process in which therelative floor positions are unchanged. An alternative approach would beto keep swapping time slots until a filled time slot was moved. Whilepossible, this approach is not preferred as it risks moving the timeslot too far in time to maintain the pitch requirement. When there is alarge number of time slots, say 100, it would be possible to performseveral swaps without departing form the pitch requirement. Thisapproach may be more appropriate on other types of trading system or inother data distribution scenarios. In the example of the preferredembodiment it is preferred that the same approach is implemented on eachbroker to ensure that all trading floors on the system are treated inthe same way and that issues of fairness are broker independent.

When swapping time slots randomly, there is a danger that a time slotthat is just about to be fired is swapped so that it is advanced infront of its firing point so that the firing is missed. Similarly, atime slot that has just been fired could be swapped backwards so that itis almost immediately fired again. This may be referred to as hoppingwhere the time slot hops over the firing point. To avoid hopping thefirst time slot of the pair to be swapped is identified ahead of timeand when it is this time slot's turn to have its market view calculated,the contents of the time slot are swapped with the following time slotbefore doing the calculation.

In FIG. 3, the time slot swapping is performed on the last timeslice ofa redistribution interval J, where J is a number of timeslices. It ispresently preferred that J=5 although this is configurable. The last, orJth timeslice is truncated to a random number R between 0 and the numberof firing slots N−1. The last timeslice is then truncated to the valueof R identifying a random swap slot in the final timeslice of the Jsequence. T=1000 mS and J=5 with N=40. The random variable R iscalculated in this example as 32 so that on the fifth or Jth timeslicethe trading floors in the 32^(nd) and 33^(rd) time slots are targeted tobe swapped around. In FIG. 3, the time slots are illustrated around thecircumference of the timeslice with the time slots filled by a tradingfloor marked by a solid circle. The two time slots to be swapped areshown as 1 and 2 and the dark bordered triangle shows the position ofthe firing point. It can be seen that the time slots are fired in aclockwise order and at the firing point, floor 1 is about to be fired.The swap is performed so that floor 2 is fired in its place and floor 1is fired immediately after. Thus hopping is avoided and the variation infiring time for each of the floors is the length of one time slot, inthis case 25 mS.

Once the process has been completed the time slice timeslice iscompleted in the usual order and the process is repeated starting fromthe end of the Jth timeslice.

In a second embodiment of the invention, the timeslice intervals areconfigurable. In a trading system, trading floors may include bothconventional trader terminals operated by human traders, and automatedtrading interfaces (Ais), which run trading algorithms. The latter Aisreact to market data much more quickly than human traders. In thisembodiment of the invention Ai terminals may be configured to receive aless frequent timeslice than a workstation. It is also desirable for anenhanced trading experience to be given to premium customers by changingthe frequency with which they receive market views. This is achieved byconfiguring each trading floor to receive market views as a givenmultiple of a basic timeslice interval.

To configure floors and Ai terminals with different timeslice intervalsthe basic timeslice is reduced to a very short interval, say ¼ second,and individual floors are instructed to take notice of every nthtimeslice. To configure a floor to have a 1 second timeslice while thebasic timeslice is ¼ second the floor is given a Floor TimesliceMultiplier of 4. This is an instruction to take notice of every fourthtimeslice. This is achieved by sending the data only every Mthtimeslice, where M is the Floor Timeslice Multiplier.

A direct implementation of this approach may not be possible as theminimum time required to wake up a thread, which is typically 20milliseconds, limits the ability of a Broker to keep up with this fasterscheduling. This problem may be overcome by grouping the time slots intoblocks. A block may have, for example, 5 to 15 time slots, preferably 10time slots. The Broker will only wake up a thread for each block of timeslots and then process each time slot in the block in sequence. Allother processing including changes in relative firing order is performedas described above with respect to FIGS. 2 and 3. Ai terminals are senta “take notice of” parameter (Ai Timeslice Multiplier A) to give them atimeslice that is a multiple of the Floor Timeslice Multiplier M for thetrading floor to which they are attached.

Thus, the Floor Timeslice Multiplier parameter, M defines the intervalbetween that Floor's Market View timeslices and specifies a number oftimeslices. If M equals zero, no workstation market view is calculatedby the broker. After each calculation and distribution of the marketview, the Broker waits M basic timeslices before processing anotherMarket View for that Floor so that market views are processed every Mthtimeslice. The Ai Timeslice Multiplier parameter, A for a Floor, definesthe interval between Ai Market View timeslices for that floor. If Aequals zero, no Ai market view is calculated by the broker, and tradingis prohibited. After each distribution of the market view to an Ai,there is a wait of A Market View updates before another Market View ispassed on to that Floor's Ai Servers.

The Broker, similarly to the first embodiment described above, keeps aschedule of timeslice firing. However, in this embodiment the scheduleis of when timeslices for different firing blocks are initiated. Theschedule is divided up into a number of equally spaced firing blocks,each block being divided into a number of time slots. When a firingblock is fired, the market view for each floor occupying a time slot iscalculated and distributed in order corresponding to their position inthe schedule. It is important that the Broker keeps a record of whethera request for a subscription to market views received from a floor isfrom a workstation (human trader) or an Ai terminal so that theappropriate multiplier can be applied.

A Basic Time Slice Frequency parameter T specifies how often thetimeslice schedule is initiated. This value also defines the schedule'sduration. One presently preferred value of T is 250 millisecondsalthough T may vary between 100 milliseconds and 5,000 milliseconds.Other values may be appropriate in other system configurations and thesevalues are not limiting. A Firing Block Count B is defined as aconfigurable parameter. A presently preferred value for B is 5. Again,this value may change according to circumstance and the value given ispurely exemplary and not limiting. It is desirable that a minimum valuefor T/B is set, which, for example, may be 50 milliseconds. Again, thisvalue is not limiting. The number of time slots in firing blocks ispreferably a configurable integer Slots in Block Count parameter N. Apresently preferred value of N is 20, which combined with the B (B×N)gives a theoretical maximum number of trading floors (including anyMarket Data pseudo floors) of 100.

It is preferable, but not essential, to have the ability to delay marketview distribution to either a Floor's Workstations or an Ai Server. Thiscan be achieved by setting two parameters: one which sets the delay forthe floor's workstations and the other which sets the delay for the AiServer.

The Floor Price Distribution Delay parameter, FD for a Floor defines theduration of the delay applied prior to distributing the Market View. TheFD parameter may specify a number of milliseconds. If FD equals zero, noworkstation delay is applied.

The Ai Price Distribution Delay parameter, AD for an Ai Server definesthe duration of the delay applied prior to distributing the Ai MarketView. The AD parameter may specify a number of milliseconds. If ADequals zero, no Ai delay is applied.

The AD and the FD parameters may be used independently of each other.However, when the AD and the FD parameters reference the same floor, theAD must be equal or greater than the FD.

FIG. 4 is similar to FIG. 3, and illustrates the principle of time slotswapping applied to the second embodiment of the invention. The FIG. 3embodiment is modified by the inclusion of the block count B (the numberof blocks in a timeslice) and the slot count N is now the number of timeslots in each block. The Redistribution Interval parameter, J defines,as a number of timeslices, the interval between the Broker'sperformances of the floor Timeslice Redistribution routine. Beforecommencing the last timeslice (the J^(th)) a random number R betweenzero and the Total Number of Slots minus one (B×N−1) is identified. Thisvalue R identifies a Random Swap Slot in the final timeslice ofJ(12^(th) in FIG. 4). Just as the slot at R is due to be fired, duringthe Jth timeslice, any contents of that slot are swapped with anycontents of the following slot (R+1). Once the reshuffle has beencompleted the process is repeated, starting from the end of the J^(th)timeslice. Any Market Data pseudo floor is redistributed among thetimeslice time slots just the same as any other floor.

Thus embodiments of the invention overcome the disadvantages of theprior art. Firstly, the division of a timeslice into time slots, and thecalculation and distribution of individual market views in each timeslot overcomes the problem of calculation to delivery latency. Secondly,random assignment of floors to time slots has the advantage of providingefficient distribution of firing. Thirdly, the random exchange of theposition of a pair of adjacent time slots during the last of every Jtimeslices overcomes the problem of long term firing proximity, ensuringthat no trading floor is caught in the shadow of an earlier floor formore than a short time. Fourthly, by ensuring that each broker or othercomputer distributing data uses timeslice of equal duration, having anequal number of time slots, it is ensured that data recipients do notreceive an unfair advantage by being attached to a particular datadistributor. As a further advantage, the relative duration of thetimeslices from floor to floor is configurable.

As mentioned above, the invention is not limited to the distributedtrading system described but is applicable to the distribution oftrading data from any trading system for example to trading floors ortrading devices. Moreover, it is applicable to the distribution of anytime critical data from one or more computers acting as datadistributors to a plurality of data recipients. When used in a tradingsystem, the invention is applicable to the trading of any tradeableproduct, including, for example, any financial instrument, where afinancial instrument is any instrument having a monetary value.

Many modifications and variations to the embodiments described aspossible and will occur to those skilled in the art without departingform the spirit and scope of the invention which is limited only by thefollowing claims.

What is claimed is:
 1. A computerized method of periodicallydistributing subsets of data to a plurality of data receivers duringeach of a plurality of data distribution periods, each data distributionperiod being divided into a plurality of time slots, the methodcomprising: using a programmed computer system to carry out at least thefollowing steps: receiving data from one or more external sources; foreach data distribution period assigning a respective data receiver to arespective time slot in that data distribution period; and during eachassigned time slot, both determining a respective subset of the receiveddata to be sent to the data receiver assigned to that time slot andsending the so determined subset of data to the data receiver assignedto that time slot.
 2. The computerized method of claim 1, wherein aplurality of the data receivers are respective trading floors.
 3. Thecomputerized method of claim 2, wherein at least one of the tradingfloors has one or more artificial intelligence data terminals and one ormore human controlled data terminals, the one or more human controlleddata terminals being a first data receiver and the one or moreartificial intelligence data terminals being a second data receiver, thefirst data receiver receiving its respective subset of data everydistribution period, the second data receiver receiving its respectivesubset of data in every Nth data distribution period, N being an integergreat than one.
 4. The computerized method of claim 1, wherein the timeslot assigned to a given data receiver is selected randomly.
 5. Thecomputerized method of claim 3, wherein the time slot assigned to agiven data receiver is selected based upon the time that data receiverconnects to the computer system in a way that allows it to beginobtaining a periodic distribution of subsets of data from the computersystem.
 6. The computerized method of claim 3, wherein each of the datadistribution periods is of equal length.
 7. The computerized method ofclaim 6, wherein each of the time slots is of equal length.
 8. Thecomputerized method of claim 1, wherein the computer system includes aplurality of programmed data distributor computers, each datadistributor computer being associated with a respective set of datareceivers and carrying out the assigning, determining and selectingsteps for its respective subset of data receivers.
 9. The computerizedmethod of claim 1, wherein the subsets of data are market datacomprising (a) prices at which a product is being offered for sale byone or more potential counterparties and/or (b) prices at which one ormore potential counterparties are offering to buy a product.
 10. Thecomputerized method of claim 9, wherein the product is a financialinstrument.
 11. The computerized method of claim 9, wherein the productis foreign currency.
 12. The computerized method of claim 1, wherein theplurality of data distribution periods are successive time periods offixed length.
 13. The computerized method of claim 1, wherein the datareceiver assigned to each time slot stays the same for J successive datadistribution periods, J being an integer great than
 2. 14. Thecomputerized method of claim 13, wherein, during the Jth datadistribution period, first and second data receivers assigned to firstand second time slots, respectively, are swapped and the data receiversassigned to the remaining slots stays the same.
 15. The computerizedmethod of claim 14, wherein the first time slot proceeds the second timeslot and wherein the swap occurs before the computer system calculatesthe subset of data to be sent during the first time slot.
 16. Thecomputerized method of claim 15, wherein the second time slotimmediately succeeds the first time slot.
 17. The computerized method ofclaim 16, wherein the determination of the first time slot to be swappedis randomly chosen during each of the Jth data distribution periods. 18.The computerized method of claim 1, wherein: the data distributionperiods are divided into successive groups of J data distributionperiods, wherein J is an integer greater than 2, and for each successivegroup of J data distribution periods, the respective data receiversassigned to respective time slots stays the same for J−1 successive datadistribution periods and the respective data receivers assigned to firstand second time slots are swapped during the Jth data distributionperiod while the respective data receivers assigned to the remainingtime slots remain the same.
 19. The computerized method of claim 18,wherein the first time slot precedes the second time slot and whereinthe swap occurs before the computer system calculates the subset of datato be sent during the first time slot.
 20. The computerized method ofclaim 19, wherein the second time slot immediately succeeds the firsttime slot.
 21. The computerized method of claim 18, wherein thedetermination of the first time slot to be swapped is randomly chosenduring each of Jth data distribution period.
 22. The computerized methodof claim 1, wherein during at least one data distribution period, thenumber of data receivers is les than the number of time slots n.
 23. Acomputerized method of periodically distributing subsets of data to aplurality of data receivers during each of a plurality of datadistribution periods, each data distribution period being divided into aplurality of time slots, the method comprising: using a programmedcomputer system to carry out at least the following steps: receivingdata from one or more external sources: for each data distributionperiod, assigning a respective data receivers to respective time slot inthat data distribution period; and for each data distribution period,dividing the data distribution period into a plurality of successiveblocks of time slots; during each block of time slots, determining arespective subset of the data to be sent to the data receivers assignedto time slots of that block; and during each time slot in a block oftime slots, sending the respective subset of data to the data receiverassigned to the respective time slot in the block.
 24. The computerizedmethod of claim 23, wherein a plurality of the data receivers arerespective trading floors.
 25. The computerized method of claim 24,wherein at least one of the trading floors has one or more artificialintelligence data terminals and one or more human controlled dataterminals, the one or more human controlled data terminals being a firstdata receiver and the one or more artificial intelligence data terminalsbeing a second data receiver, the first data receiver receiving itssubset of data every distribution period, the second data receiverreceiving its subset of data in every Nth data distribution period, Nbeing an integer great than one.
 26. The computerized method of claim23, wherein the time slot assigned to a given data receiver is selectedrandomly.
 27. The computerized method of claim 23, wherein the time slotassigned to a given data receiver is selected based upon the time thatdata receiver connects to the computer system in a way that allows it tobegin obtaining a periodic distribution of subsets of data from thecomputer system.
 28. The computerized method of claim 23, wherein eachof the data distribution periods is of equal length.
 29. Thecomputerized method of claim 28, wherein each of the time slots is ofequal length.
 30. The computerized method of claim 23, wherein thecomputer system includes a plurality of programmed data distributorcomputers, each data distributor computer being associated with arespective set of data receivers and carrying out the assigning,determining and selecting steps for its respective subset of datareceivers.
 31. The computerized method of claim 23, wherein the subsetsof data are market data comprising (a) prices at which a product isbeing offered for sale by one or more potential counterparties and/or(b) prices at which one or more potential counterparties are offering tobuy a product.
 32. The computerized method of claim 31, wherein theproduct is a financial instrument.
 33. The computerized method of claim31, wherein the product is foreign currency.
 34. The computerized methodof claim 23, wherein the plurality of data distribution periods aresuccessive time periods of fixed length.
 35. The computerized method ofclaim 23, wherein the data receiver assigned to each time slot stays thesame for J successive data distribution periods, J being an integergreat than
 2. 36. The computerized method of claim 35, wherein, duringthe Jth data distribution period, first and second data receiversassigned to first and second time slots, respectively, are swapped andthe data receivers assigned to the remaining slots stays the same. 37.The computerized method of claim 36, wherein the first time slotproceeds the second time slot and wherein the swap occurs before thecomputer system calculates the subset of data to be sent during thefirst time slot.
 38. The computerized method of claim 37, wherein thesecond time slot immediately succeeds the first time slot.
 39. Thecomputerized method of claim 38, wherein the determination of the firsttime slot to be swapped is randomly chosen during each of the Jth datadistribution periods.
 40. The computerized method of claim 23 wherein:the data distribution periods are divided into successive groups of Jdata distribution periods, wherein J is an integer greater than 2, andfor each successive group of J data distribution periods, the respectivedata receivers assigned to respective time slots stays the same for J−1successive data distribution periods and the respective data receiversassigned to first and second time slots are swapped during the Jth datadistribution period and the respective data receivers assigned to theremaining slots stay the same.
 41. The computerized method of claim 40,wherein the first time slot proceeds the second time slot and whereinthe swap occurs before the computer system calculates the subset of datato be sent during the first time slot.
 42. The computerized method ofclaim 41, wherein the second time slot immediately succeeds the firsttime slot.
 43. The computerized method of claim 41, wherein thedetermination of the first time slot to be swapped is randomly chosenduring each of Jth data distribution period.
 44. The computerized methodof claim 23, wherein during at least one data distribution period, thenumber of data receivers is less than the number of time slots.
 45. Thecomputerized method of claim 23, wherein only a subset of the marketdata is sent to one or more of the data receiver terminals.